<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<HTML>
<HEAD>
<META name="generator" content="mm2html (AT&amp;T Research) 2012-01-11">
<TITLE> www/ksh/ksh.mm mm document </TITLE>
<META name="author" content="gsf+dgk+kpv">
<STYLE type="text/css">
div.FI	{ padding-left:2em; text-indent:0em; }
div.HI	{ padding-left:4em; text-indent:-2em; }
dt	{ float:left; clear:both; }
dd	{ margin-left:3em; }
</STYLE>
</HEAD>
<BODY bgcolor=white link=slateblue vlink=teal >
<TABLE border=0 align=center width=96%>
<TBODY><TR><TD valign=top align=left>
<!--INDEX--><!--/INDEX-->


<P>
<P><CENTER><FONT color=red><FONT face=courier><H3><A name="ksh overview">ksh overview</A></H3></FONT></FONT></CENTER>
The
<STRONG>KornShell</STRONG>
language was designed and developed by David G. Korn at AT&amp;T Bell Laboratories and AT&amp;T Research.
It is an interactive command language that provides access to the UNIX system and to many other systems,
on the many different computers and workstations on which it is implemented.
The
<STRONG>KornShell</STRONG>
language is also a complete, powerful, high-level programming language for writing applications,
often more easily and quickly than with other high-level languages.
This makes it especially suitable for prototyping.
There are two other widely used shells, the Bourne shell developed by Steven Bourne at AT&amp;T Bell Laboratories,
and the C shell developed by Bill Joy at the University of California.
<STRONG>ksh</STRONG>
has the best features of both, plus many new features of its own.
Thus
<STRONG>ksh</STRONG>
can do much to enhance your productivity and the quality of your work,
both in interacting with the system, and in programming.
<STRONG>ksh</STRONG>
programs are easier to write, and are more concise and readable than programs written in a lower level language such as C.
<P>
The new version of
<STRONG>ksh</STRONG>
has the functionality of other scripting languages such as awk, icon, perl, rexx, and tcl.
For this and many other reasons,
<STRONG>ksh</STRONG>
is a much better scripting language than any of the other popular shells.
The code size for
<STRONG>ksh</STRONG>
is larger than the Bourne shell or C shell programs.
The revised version is even larger.
<P>
In spite of its increased size,
<STRONG>ksh</STRONG>
provides better performance.
You can write programs to run faster with
<STRONG>ksh</STRONG>
than with either the Bourne shell or the C shell, sometimes an order of magnitude faster.
<STRONG>ksh</STRONG>
has evolved and matured with extensive user feedback.
It has been used by many thousands of people at AT&amp;T since 1982, and at many other companies and universities.
A survey conducted at one of the largest AT&amp;T Bell Laboratories computer centers showed that 80% of their customers, both programmers and non-programmers, use
<STRONG>ksh.</STRONG>
<STRONG>ksh</STRONG>
is compatible with the Bourne shell.
Virtually all programs written for the Bourne shell run with
<STRONG>ksh.</STRONG>
If you are familiar with the Bourne shell, you can use
<STRONG>ksh</STRONG>
immediately, without retraining.
The new version of
<STRONG>ksh</STRONG>
is compatible with earlier versions of
<STRONG>ksh.</STRONG>
<STRONG>ksh</STRONG>
is readily available.
It is sold (source and binary) by AT&amp;T and Novell, and by other companies under license from AT&amp;T both in the USA and abroad.
It has been purchased by dozens of major corporations, and by many individuals for use on home computers.
<STRONG>ksh</STRONG>
is extensible.
<P>
The
<STRONG>KornShell</STRONG>
language uses the same syntax for built-in commands as for non built-in commands.
Therefore, system developers can add new commands "transparently" to the
<STRONG>KornShell</STRONG>
language; that is, with minimum effort and with no differences visible to users other than faster execution.
On systems with dynamic linking, it is possible to add new built-in commands at run time.
Novell has extended the new version of
<STRONG>ksh</STRONG>
to enable X-windows programming for their desktop
<STRONG>ksh</STRONG>
product,
<STRONG>dtksh</STRONG>.
<STRONG>dtksh</STRONG>
is a standard part of CDE, the Common Desktop Environment defined by COSE (Common Operating System Environment), supported by most major UNIX system hardware vendors.
An extended version of
<STRONG>ksh</STRONG>
that enables Tk programming, called tksh, is available as well.
<P>
<STRONG>ksh</STRONG>
is intended to conform to the Shell Language Standard developed by the IEEE POSIX 1003.2 Shell and Utilities Language Committee.
<P>
<HR>
<TABLE border=0 align=center width=96%>
<TR>
<TD align=left></TD>
<TD align=center></TD>
<TD align=right>March 13, 2012</TD>
</TR>
</TABLE>
<P>

</TD></TR></TBODY></TABLE>

</BODY>
</HTML>
